Nanostructured surface for microparticle analysis and manipulation

ABSTRACT

The present invention provides an apparatus, comprising a first mechanical structure having a first rigid surface, an area of the first rigid surface having a nanostructured surface. The apparatus also includes a second mechanical structure having a second rigid surface and opposing the first mechanical structure. The second rigid surface is cooperable with the nanostructured surface such that a microscopic particle is locatable between the nanostructured surface and the second rigid surface.

TECHNICAL FIELD OF THE INVENTION

The present invention is directed, in general, to an apparatus andmethods for testing and rupturing microparticles.

BACKGROUND OF THE INVENTION

In many biological applications, it is desirable to rupturemicroparticles so that their contents can be analyzed, or to identify orcharacterize intact microparticles. For instance, there is greatinterest in the development of cost effective and rapid methods formonitoring the presence and concentration of bacterial or other cells inmilitary, medical, agricultural and food preparation applications. Theanalysis of cells often requires that they be ruptured, so that thecontents of the cells can be analyzed. For certain microparticle types,however, rupturing is problematic.

For instance, when stressed or starved for nutrients, vegetativebacterial cells can differentiate into dormant endospores, more commonlyreferred to as spores. Spores are highly resistant to inactivation andrupture by various physical treatments, including mechanical agitation,ultraviolet and gamma radiation, heat, and chemical treatments. The needfor bulky complex equipment, such as microwave or ultrasonicinstrumentation, to accomplish rupturing, adds significantly to thecost, and decreases the speed, of detecting and analyzing such cells. Inaddition, the harsh conditions presently used for rupturing caninadvertently damage the contents of the cells. For example, rupture viathe chemical action of surfactants, or the physical stress provided bysonication, can damage or denature DNA, protein, or other components inthe cell. Similar concerns exist for the analysis of non-biologicalmicroparticles.

The present invention overcomes these problems by providing an apparatusthat uses nanostructured surfaces to facilitate the rupture or testingof microparticles, as well as methods of using and making such anapparatus.

SUMMARY OF THE INVENTION

To address the above-discussed deficiencies, one embodiment of thepresent invention provides an apparatus comprising a first and a secondmechanical structure. The first mechanical structure has a first rigidsurface. An area of the first rigid surface has a nanostructuredsurface. The second mechanical structure has a second rigid surface. Thesecond rigid surface opposes the first mechanical structure and iscooperable with the nanostructured surface such that a microscopicparticle is locatable between the nanostructured surface and the secondrigid surface.

Another embodiment of the invention is a method of use. The methodincludes placing a plurality of microscopic particles in an embodimentof the above-described apparatus and applying a force to the pluralityof microscopic particles using the nanostructured surface and the secondrigid surface.

Yet another embodiment of the present invention is a method ofmanufacturing an apparatus. The method of manufacture includes forming afirst mechanical structure having a first rigid surface and forming ananostructure in an area of the first rigid surface. The method ofmanufacture also includes forming a second mechanical structure having asecond rigid surface. The second mechanical structure is positioned sothat the second rigid surface opposes the first mechanical structure andis cooperable with the nanostructure such that the surfaces apply aforce to microscopic particles locatable between the nanostructure andthe second rigid surface.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is best understood from the following detaileddescription, when read with the accompanying FIGUREs. Various featuresmay not be drawn to scale and may be arbitrarily increased or reducedfor clarity of discussion. Reference is now made to the followingdescriptions taken in conjunction with the accompanying drawings, inwhich:

FIG. 1 illustrates a cross-sectional view of an exemplary apparatus forapplying a contact force to a microparticle;

FIG. 2 illustrates a cross-sectional view of a second exemplaryapparatus for applying an electric current to a microparticle;

FIG. 3 illustrates a cross-sectional view of a third exemplary apparatusfor applying an electric field to a microparticle;

FIG. 4 illustrates a cross-sectional view of a fourth exemplaryapparatus for applying an acoustic wave to a microparticle;

FIGS. 5-6 illustrate cross-sectional views of an exemplary apparatus atselected stages in a method to rupture a microparticle; and

FIGS. 7-10 illustrate cross-sectional views of an exemplary method ofmanufacturing an apparatus according to the principles of the presentinvention.

DETAILED DESCRIPTION

The present invention recognizes the advantageous use of nanostructuresto facilitate the testing or rupture of microparticles. Nanostructuredsurfaces are desirable because they provide a small area of contact and,therefore, promote the development of high stresses at ananostructure-microparticle surface. The term nanostructured surface asused herein is defined as a surface having an array of protrudingstructures, each structure having lateral dimensions ranging from about50 nanometers to about 1000 nanometers. Nanostructured surfaces can beadvantageously used to rupture a microparticle with a minimum of damageto its contents, as compared to conventional rupturing techniques thatuse regular unstructured surfaces. Nanostructures can also beadvantageously used to facilitate the collection of information aboutthe microparticle. Such information can include measuring of the elasticproperties of microparticles, determining when a microparticle has beenruptured, or establishing the identity of a microparticle.

FIG. 1 illustrates a cross sectional view of a portion of an exemplaryapparatus 100 for applying a contact force to a microparticle. Theapparatus 100 comprises a first mechanical structure 105 having a firstrigid surface 110. An area 115 of the first rigid surface 110 has ananostructured surface 120. The apparatus 100 further includes a secondmechanical structure 125 having a second rigid surface 130. The secondrigid surface 130 opposes the first mechanical structure 105 and iscooperable with the nanostructured surface 120 such that a microscopicparticle 135 is locatable between the nanostructured surface 120 and thesecond rigid surface 130.

One of ordinary skill in the art would appreciate that there arenumerous ways that the nanostructured surface 120 and the second rigidsurface 130 can cooperate to locate the microparticle 135 between thesecond rigid surface 130 and the nanostructured surface 120. In theexemplary apparatus 100 shown in FIG. 1, the second rigid surface 130 ispositioned a distance 137 over the nanostructured surface 120 such thatthe microscopic particle 135 can be located between the nanostructuredsurface 120 and the second rigid surface 130. The distance 137 betweenthe nanostructured surface 120 and the second rigid surface 130 can beadjusted to help retain the microscopic particle 135 between thesesurfaces 120, 130. For instance, in some cases, the distance 137 is lessthan about twice an average diameter 139 of the microparticle 135.

The nanostructured surface 120 can be made by dry etching the surface110 of the first mechanical structure 105 using procedures well known tothose skilled in the art. The first and second mechanical structures105, 125 can comprise a first and second semiconductor substrate,respectively, such as silicon wafers. In some instances, it isadvantageous for the second rigid surface 130 to also have ananostructured surface.

FIG. 1 shows a preferred nanostructured surface 120 that comprises pins140. The term pin is used herein to refer to structures having varietyof shapes, including cylindrical, square, triangular, prisms, pyramids,rectangular-shaped structures or combinations thereof. In some cases,for instance, the nanostructured surface 120 can have blades 142, suchas unidirectional blades, configured to rupture the microparticle 135.In some cases, it is advantageous to arrange the pins 140 into aone-dimensional array to form a saw or a two-dimensional array to formgrass-shaped structures. For instance, FIG. 1 shows a cross-sectionalview of a nanostructured surface 120 comprising nanograss 145.

The microparticle 135 can comprise biological cells, including plant,animal or bacterial cells. In some cases, the microparticle 135 is abacterial spore, such as Bacillus anthracis, subtilis, or thuringiensis.Alternatively, the microparticle 135 can comprise a nonbiologicalparticle, such as a microsphere. Some preferred microspheres comprise alatex sphere holding chemicals inside the sphere. In some embodiments ofthe apparatus 100, more than one microparticle 135 can be locatedbetween the nanostructured surface 120 and the second rigid surface 130.

In the embodiment depicted in FIG. 1, one or both of the first rigidsurface 110 and the second rigid surface 130 are movable with respect toeach other and can thereby cooperate to apply a contact force to themicroscopic particle 135 through the nanostructured surface 120. Certaindesirable embodiments of the nanostructured surface 120 help to ensurethat the nanostructured surface 120 contacts the microparticle 135.Advantageous nanostructured surfaces 120 can include pins 140 configuredto have a pitch 150 that is smaller than about one-half of an averagediameter 155 of the microscopic particle 135. In some cases, the pin 140has a diameter 160 that is less than about one tenth of the averagediameter 155 of the microparticle 135.

It is desirable for the first and said second rigid surfaces 110, 130 tobe substantially planar because this helps ensure that the contact forceis applied in a well-controlled manner, regardless of themicroparticle's 135 location between the nanostructured surface 120 andthe second rigid surface 130. In addition, positioning the first andsaid second rigid surfaces 110, 130 to be substantially parallel to eachother helps to hold the microparticle 135 between the nanostructuredsurface 120 and the second rigid surface 130 while the contact force isapplied. In other cases, however, one or both of the first and saidsecond rigid surfaces 110, 130 can have convex, concave, or othershapes.

When the contact force is designed to rupture the microparticle 135, itis desirable for the pin's diameter 160 to be configured to facilitatelysing of a membrane or coating 165 of the microparticle 135. In somecases, the diameter 160 is less than about 1 micrometer, and morepreferably less than about 400 nanometers. It is sometimes desirable forthe pins 140 to have a narrowed or pointed tip, because this facilitatesa highly localized force being applied to the microparticle 135,resulting in efficient rupture of its membrane or coat 165. In somecases, the tip diameter 170 is one-half to one-tenth of the pin diameter160.

In other cases, the contact force is designed to gather informationabout the microparticle 135, such as the microparticle's 135 elasticproperties. For instance, applying an incrementally increasing contactforce to the microparticle 135 allows the compressibility of themicroparticle 135 to be assessed. A measurement of compressibility canbe used to identify the state of the microparticle 135, e.g., vegetativeversus active bacterial cells. In such applications, to avoid rupturingthe microparticle 135, it can be desirable for the tip diameter 170 tobe about the same length as the pin diameter 160.

As shown in FIG. 1, both the pin pitch 150 and height 175 can be uniformthroughout the area 115 comprising the nanostructured surface 120. Insome preferred embodiments of the apparatus 100, the pitch 150 rangesfrom about 0.5 to about 5 micrometers. In some cases, however, it isadvantageous for the pitch 150 throughout the area 115 to be nonuniform,because this permits a contact force to be applied to differently sizedmicroparticles 135. A nonuniform pitch 150 can also facilitate theapplication of different forces to same-size microparticles 135positioned at different locations in the area 115. A nonuniform pitch150 can also help retain the microparticle 135 between the nanostructuresurface 120 and second rigid surface 130. For similarly reasonsdiscussed above, it can be beneficial for the height 175 of the pins 140to be nonuniform. In some cases, the height 175 ranges from about 1micrometer to 7 micrometers.

As further illustrated in FIG. 1, some embodiments of the apparatus 100further comprise a system 180 configured to analyze material releasedfrom the microparticle 135 when it is ruptured. Non-limiting examples ofthe system 180 include machines to conduct immunological or nucleic acidassays, chromatographic and spectroscopic analysis, or combinationsthereof. In some embodiments, the system 180 is coupled to the apparatus100 via a channel 182, such as a microfluidic channel, that directsmaterials or chemicals released from the microparticle 135 to the system180. It can be advantageous for the one or both of the first rigidsurface 110 or the second rigid surface 130 to further comprise openings185 to form a permeable membrane 190. In the embodiment shown in FIG. 1,the area 115 of the first rigid surface 110 comprises the openings 185.

The apparatus 100 can further comprise a device 195, such as a pump orother hydraulic machine, configured to pass material released from themicroparticle 135 through the openings 185. For instance, the device 195can facilitate passage by irrigating supplemental material across thepermeable membrane 190, including a chemically reactive substance suchas a detergent or denaturant, or a liquid, such as water.

FIG. 2 illustrates a cross-sectional view of a second exemplaryapparatus 200 for applying an electric current to a microparticle 135.Elements of the apparatus 200 that are analogous to the apparatus shownin FIG. 1 are assigned the same reference number. The first rigidsurface 110 and the second rigid surface 130 of the apparatus 200 cancooperate to apply a force comprising an electromagnetic force to themicroscopic particle 135 through the nanostructured surface 120. Forinstance, passing an electric current through the pins 205 and to thesurface 165 of the microparticle 135 generates an electromagnetic forceon the microparticle 135.

In preferred embodiments of the apparatus 200, such as shown in FIG. 2,the nanostructured surface 120 comprises pins 205 having a conductivecore 210. The conductive core 210 and the second rigid surface 130 areelectrically coupled to a voltage source 215. As shown in FIG. 2, aplurality of conductive cores 210 can be electrically coupled to eachother via one or more conductive lines 217 in the first mechanicalstructure 105. The conductive core 210 and line 217 can comprise dopedsilicon. The conductive core 210 and the second rigid surface 130 areconfigured to transmit an electrical current to the microparticle 135when the voltage source 215 applies a voltage potential between theconductive cores 210 and the second rigid surface 130.

The strength of current passed to the microparticle 135 can be varied byapplying different voltages as appropriate, either to gather informationabout the microparticle's 135 properties, or to rupture themicroparticle 135. Low voltages (e.g., less than about 1 Volt) can beused to generate sufficient current through the conductive core 210 ofthe pins 205 to produce extremely high, localized power dissipation.This, in turn, causes thermal damage or electrical breakdown, which inturn, can rupture the microparticle's membrane or coat 165.

Still lower voltages (e.g. less than about 0.1 Volts) can be used tomeasure the microparticle's 135 electrical properties. Theidentification of different species of cells by measuring theirelectrical properties such as their capacitance, impedance orconductance, is well known to one of ordinary skill in the art. Seee.g., T C Chang and A H Huang, Journal of Clinical Microbiology, October2000, p. 3589-3594, Vol. 38, No. 10, incorporated by reference herein inits entirety. In some embodiments of the apparatus 200, to measureelectrical impedance, a current is passed from the conductive core 210through the microparticle 135 and to the second rigid surface 130. Theelectrical impedance of the microparticle 135 can differ depending onits identity, e.g., different electrical impedance for different typesof bacteria. The electrical impedance of the microparticle 135 can alsodiffer depending on whether or not the microparticle 135 has ruptured,or depending on the state of the microparticle 135, e.g., vegetativeversus active bacterial cells. For example, rupturing a microparticle135 can cause its contents, e.g., cytoplasm, to spill out into thesurrounding fluid, increasing conductivity and causing a detectablechange in electrical impedance.

Those skilled in the art are familiar with the procedures used tofabricate pins 205 having a conductive core 210, for example, by dryetching a doped silicon substrate. In some cases, as shown in FIG. 2,the pins 205 further include an insulating layer 220, and only the tip225 of the conductive core 210 is uninsulated. Such an arrangement canadvantageously pass a larger current to the microparticle 135, for agiven voltage potential, than using an uninsulated conductive core 210.The procedures to make the insulating layer 220 are also well known tothose skilled in the art. For instance, the insulating layer 220 cancomprise silicon dioxide conformally grown around the conductive core210 by a conventional thermal oxidation process, and the conductive tip225 exposed by a conventional etch process.

FIG. 3 illustrates a cross-sectional view of a third exemplary apparatus300 for applying an electric field to a microparticle 135. Elements ofthe apparatus 300 that are analogous to the apparatuses shown in FIGS. 1and 2 are given the same reference number. The first rigid surface 110and the second rigid surface 130 of the apparatus 300 can cooperate toapply a force comprising an electrical force to the microscopic particle135 through the nanostructured surface 120.

Similar to the apparatus presented in FIG. 2, preferred embodiments ofthe apparatus 300 comprise pins 305 having a conductive core 310 coveredwith an insulating layer 315. The conductive core 310 and the secondrigid surface 130 are electrically coupled to a voltage source 215. Theconductive core 310 and the second rigid surface 130 are configured toapply an electrical field to the microparticle 135 when the voltagesource 215 applies a voltage between the conductive core 310 and thesecond rigid surface 130. For instance, applying a voltage can produce ahigh, localized electric field at the tip 320 of the pin 305 that can beused to gather information about the properties of the microparticle135, or to rupture the microparticle 135.

One of ordinary skill in the art would be familiar with the variouselectrokinetic techniques, such as dielectrophoresis andelectrorotation, to manipulate, separate or rupture microparticles 135.See e.g., M. P. Hughes, AC Electrokinetics: Applications forNanotechnology, in The Seventh Foresight Conference on MolecularNanotechnology, Oct. 15-17, 1999, Santa Clara, Calif.; and U.S. PatentApplication No. 2003/0186430, both incorporated by reference herein intheir entirety. For instance, if a dielectric microparticle 135, such asa cell, is exposed to an external electric field it will polarize. Thesize and direction of the induced dipole will depend on the fieldfrequency and dielectric properties of the microparticle 135 (e.g., itsconductivity and permittivity). An inhomogeneous field will cause theelectrical force due to the interaction of induced dipole and externalfield.

FIG. 4 illustrates a cross-sectional view of a fourth exemplaryapparatus 400 for applying an acoustic wave to a microparticle 135.Elements of the apparatus 400 that are analogous to the apparatus shownin FIG. 1 are given the same reference number. The first rigid surface110 and the second rigid surface 130 of the apparatus 400 can cooperateto apply a force comprising an acoustic wave to the microscopic particle135 through the nanostructured surface 120.

Similar to the apparatus 100 presented in FIG. 1, preferred embodimentsof the apparatus 400 comprise pins 405. The pins 405 can have any of thestructures or shapes, or combinations thereof, discussed above and shownin FIGS. 1-3. The apparatus 400 further includes a device 410 configuredto generate an acoustic wave that is passed to at least one of the firstor second rigid surfaces 110, 130. In some cases, the device 410comprises a piezoelectric material and, as shown in FIG. 4, is coupledto the first rigid surface 110 adjacent to the area 115 of the firstmechanical structure 105 where the nanostructured surface 120 islocated. In some embodiments of the apparatus 400, the piezoelectricmaterial is configured to apply an ultrasonic wave to the pins 405.

An oscillatory potential applied to the piezoelectric material of thedevice 410 causes an acoustic force to be transferred from the pins 405to the microparticle 135. The acoustic force can be used to rupture, oralternatively, gather information about the microparticle 135. Certainwavelengths of the ultrasonic wave cooperate with the pins 405 to alterthe acoustic force by inducing diffraction and interference effects tothe ultrasonic waves as they propagate through the pins 405. This, inturn, can produce a focusing effect on the acoustic force at the tips415 of the pins 405. For instance, an acoustic wave can travel down thelongitudinal axis 420 of the pins 405 and come out at the tips 415.Acoustic waves having a wavelength comparable to the diameter 425 of thepins 405 are contained inside the pins 405, resulting in a more focusedacoustic force emanating from the tips 415. In some instances, a greaterfocusing of the acoustic force is achieved by providing pins 420 with ahemispherical tip 430 or conical tip 435. In some cases, additionalfocusing of the acoustic force is achieved by providing acoustic waveshaving a wavelength comparable to the lateral spacing 440 between pins405.

In certain embodiments of the apparatus 400 one or more transducers 445collect reflected or refracted acoustic waves for analysis. Forinstance, measuring acoustic impedance, the product of themicroparticle's sound speed multiplied by the microparticle's density,can establish whether or not the microparticle 135 has ruptured.Similarly, the acoustic impedance of the microparticle 135 can be usedto establish its state, e.g., vegetative versus active bacterial cells,or identity, e.g., a particular species of bacterial cell.

For clarity, various aspects of the above apparatuses have beendiscussed separately and presented in FIGS. 1-4. An apparatus of thepresent invention, however, could include all or some of theabove-described nanostructured surfaces, including pins, and othercomponents, such as the system 180, openings 185, membrane 190 anddevice 195 discussed in the context of FIG. 1. As an example, withcontinuing reference to FIGS. 1 and 4, the area 115 can comprise pins140, 405 are configured to rupture the microparticle 135 from theapplication of either or both a contact force and an acoustic forcethrough the nanostructured surface 120. Apparatuses that provide othercombinations of mechanical, electric current, electric field andacoustic forces as well as solvents delivered through the openings 185would be readily apparent to one of ordinary skill in the art.Similarly, the above-mentioned combinations of various forces can beused not only to accomplish rupture of the microparticle 135, but alsoto analyze its physical properties (mechanical, electrical, etc . . . )either simultaneously with the rupture process or in a separate process.

Another embodiment of the present invention is a method of use. FIGS.5-6 illustrate cross-sectional views of an exemplary apparatus atselected stages in a method to rupture a microparticle. Turning first toFIG. 5, illustrated is the apparatus 500 after placing a microparticle505 in the apparatus 500. The apparatus 500 can comprise any of theembodiments discussed above and shown in FIGS. 1-4. As illustrated inFIG. 5, a first mechanical structure 510 has a first rigid surface 515,with an area 520 of the first rigid surface 515 having a nanostructuredsurface 525. As further shown in FIG. 5, in some instances, the firstmechanical structure 510 comprises a fixed stage 530 having a siliconsubstrate 535 thereon. The area 520 comprises a portion of the siliconsubstrate 535 that is dry etched to form a nanostructured surface 525comprising nanopins 540.

The apparatus 500 further includes a second mechanical structure 545having a second rigid surface 550 opposing the first mechanicalstructure 510. In the embodiment shown in FIG. 5, the second rigidsurface 550 also has a second nanostructured surface 552 comprising pins554. In the particular embodiment shown, to facilitate microparticle 505lysing, the pins 554 of the second nanostructured surface 552 are offsetfrom the pins 540 of the nanostructured surface 525 to form a pair ofinterdigitated nanostructured surfaces 525, 552. The second mechanicalstructure 545 can also comprise a translation stage 555, having a secondsubstrate 560 thereon, the second substrate 560 comprising the secondrigid surface 550. The translation stage 555 can comprise a springloaded device, such as that used in microscope stages ormicromanipulators, to facilitate the precise movement of the secondrigid surface 550 opposing the first mechanical structure 510.

As illustrated in FIG. 5, the second rigid surface 550 can cooperatewith the nanostructured surface 525 such that the microscopic particle505 is located between the nanostructured surface 525 and the secondrigid surface 550. A distance 565 between the nanostructured surface 525and the second rigid surface 550 can be adjusted to help keep themicroscopic particle 505 located between these surfaces 525, 550 whileusing the apparatus 500. In some cases, the distance 565 is less thanabout twice an average diameter 570 of the microparticle 505.Alternatively, the shape of the nanostructured surface 525 and thesecond rigid surface 550 can be adjusted to help keep the microparticle505 between these surfaces 525, 550. As shown in FIG. 5, both thenanostructured surface 525 and the second rigid surface 550 can have aplanar shape and be parallel to each other. In other cases, however, thenanostructured surface 525 has a convex shape and the second rigidsurface 550 has a concave shape. As noted above, other combinations ofshaped surfaces are also within the scope of the present invention.

Referring now to FIG. 6, illustrated is the apparatus 500 after applyinga force to the microscopic particle 505 using the nanostructured surface525 and the second rigid surface 550. For the particular embodiment ofthe method illustrated in FIG. 6, the force is a contact force generatedwhen the first and second rigid surfaces 515, 550 are moved towards eachother. For instance, the second rigid surface 550 is moved towards thenanostructured surface 525 to produce a contact force sufficient torupture the microscopic particle 505, for example, by lysing itssurrounding membrane or coating 605.

It will be readily apparent from the above discussion that other typesof forces can be applied to the microparticle 505. The force cancomprise an electric field or current generated when a voltage isapplied across the nanostructured surface 525 and the second rigidsurface 550. Additionally, the force can comprise an ultrasonic wavewhen an acoustic force is applied to one or both of the first or secondrigid surfaces 515, 550.

Yet another embodiment of the present invention is a method ofmanufacturing an apparatus. FIGS. 7-10 illustrate cross-sectional viewsof an exemplary method of manufacturing an apparatus 700 according tothe principles of the present invention. Any of the above-discussedembodiments of the apparatus shown in FIG. 1-6 can be incorporated intothe method of manufacture.

Turning now to FIG. 7, illustrated is the partially constructedapparatus 700 after forming a first mechanical structure 705 having afirst rigid surface 710. In some cases, the first mechanical structure705 comprises a semiconductor substrate, such as a silicon wafer, and insome cases include a surface material offering increased mechanicalrigidity, e.g., a SiO₂ layer, a silicon nitride layer, or anelectroplated metal layer.

Referring now to FIG. 8, shown is the partially constructed apparatus700 after forming a nanostructure 805 in an area 810 of the first rigidsurface 710. As shown, the nanostructure 805 can comprise a surface 815having pins 820, which in this case, form nanograss 825. The pins 820can be formed using conventional photolithographic and dry etchingprocedures, for example, to remove portions of the first mechanicalstructure 705. Alternatively, the nanostructure 805 can be formed bypatterning the surface 815 with a photoresist, electroplating a metalsuch as nickel over the pattern, and removing the photoresist. Otherconventional methods of forming the nanostructure 805 would be readilyapparent to one of ordinary skill in the art.

FIG. 9 depicts the partially constructed apparatus 700 after forming asecond mechanical structure 905 having a second rigid surface 910. Insome instances, the second mechanical structure 905 comprises a secondsemiconductor substrate such as a silicon wafer. In some cases, asshown, the second rigid surface 910 is planar, although in other cases aportion of the second rigid surface 910 is patterned to form ananostructure that can be the same or different than the nanostructure805 of the first rigid surface 710.

As further illustrated in FIG. 10, the second mechanical structure 905is positioned to oppose the first mechanical structure 705. The secondmechanical structure 905 is cooperable with the nanostructure 805 suchthat a microscopic particle 1005 is locatable between the nanostructure805 and the second rigid surface 910. For instance, positioning caninclude adjusting a distance 1010 between the nanostructure 805 and thesecond rigid surface 910 to be less than about 2 times an averagediameter 1015 of the microparticle 1005.

Although the present invention has been described in detail, those ofordinary skill in the art should understand that they can make variouschanges, substitutions and alterations herein without departing from thescope of the invention.

1. An apparatus, comprising: a first mechanical structure having a firstrigid surface, an area of said first rigid surface having a nanostructured surface; and a second mechanical structure having a secondrigid surface and opposing said first mechanical structure andcooperable with said nanostructured surface such that a microscopicparticle is locatable between said nanostructured surface and saidsecond rigid surface, and wherein: one of said rigid surfaces is movablewith respect to the other of said rigid surfaces and cooperable to applya contact force to said microscopic particle through said nanostructuredsurface, said nanostructured surface comprises pins having a conductivecore, said conductive core and said second rigid surface configured tobe electrically coupled to a voltage, and said area of said first rigidsurface includes openings between said pins to form a permeablemembrane.
 2. The apparatus of claim 1, wherein said nanostructuredsurface comprises pins configured to have a pitch equal to smaller thanabout one-half of an average diameter of said locatable microscopicparticle.
 3. The apparatus of claim 1, wherein said second rigid surfacefurther comprises openings to form a second permeable membrane.
 4. Theapparatus of claim 1, wherein: said conductive core of each of said pinsis insulated.
 5. The apparatus of claim 1, further comprising a deviceconfigured to generate an acoustic wave applied to at least one of saidfirst rigid surface or said second rigid surface.
 6. The apparatus ofclaim 1, wherein said nanostructured surface comprises a plurality ofblades having a diameter configured to rupture a membrane of saidlocatable microparticle.
 7. The apparatus of claim 1, further comprisinga system configured to analyze material released from said locatablemicroparticle when said microparticle is ruptured.
 8. The apparatus ofclaim 1, further comprises a device configured to pass analyzed materialreleased from said microparticle through said openings.
 9. The apparatusof claim 1, wherein said microparticle is located between saidnanostructured surface and said second rigid surface.
 10. The apparatusof claim 9, wherein said microparticle is a biological cell.
 11. Theapparatus of claim 9, wherein said microparticle is a nonbiologicalparticle.
 12. The apparatus of claim 9, wherein said contact force lysesa membrane or a coating of said microparticle.
 13. The apparatus ofclaim 1, wherein said second rigid surface further includes a secondnanostructured surface.
 14. The apparatus of claim 13, wherein pins ofsaid second nanostructured surface are offset from pins of saidnanostructured surface.
 15. The apparatus of claim 1, wherein saidnanostructured surface has a one of a convex or concave shape and saidsecond rigid surface has the other of said convex or concave shape. 16.The apparatus of claim 1, further comprising: a system configured toanalyze material released from ruptured ones of said microscopicparticles; a microfluidic channel that directs said material to saidsystem; and a device configured to pass said material through openingsin one or both of said first or second rigid surfaces to said system.17. The apparatus of claim 1, further comprising: a system configured toanalyze a physical property of said microparticle in response to saidcontact force being applied.
 18. The apparatus of claim 17, wherein saidphysical property is one or more of an elastic property orcompressibility of said microparticle, assessed by applying said contactforce between said microparticle and pins of said nanostructuredsurface.
 19. The apparatus of claim 17, wherein pins of saidnanostructured surface have tip diameters that are substantially equalto pin diameters.
 20. The apparatus of claim 17, wherein said physicalproperty is one or more of a capacitance, impedance or conductance ofsaid microparticle, assessed by applying a voltage potential betweensaid microparticle and conductive pins of said nanostructured surface.21. The apparatus of claim 20, wherein said voltage potential is lessthan about 0.1 Volts.
 22. The apparatus of claim 17, wherein saidphysical property is one or more of a dielectric property of saidmicroparticle, assessed by resistance or a conductance between saidmicroparticle and insulated conductive pins of said nanostructuredsurface.
 23. The apparatus of claim 17, wherein said physical propertyis an acoustic impedance of said microparticle, assessed by applying anacoustic wave between said microparticle and said nano structuredsurface.
 24. The apparatus of claim 17, wherein said apparatus isconfigured to apply to said microparticle, acoustic waves of awavelength substantially equal to a lateral spacing between pins of saidnanostructured surface.
 25. The apparatus of claim 1, further includingsaid voltage source, wherein said conductive core and said second rigidsurface are electrically coupled to said voltage source.